Merge pull request #74 from SciML/compathelper/new_version/2021-12-24-00-50-42-110-03157870388

CompatHelper: bump compat for ModelingToolkit to 8, (keep existing compat)

Author: ChrisRackauckas

Project.toml

@@ -13,7 +13,7 @@ Symbolics = "0c5d862f-8b57-4792-8d23-62f2024744c7"
 [compat]
 Catalyst = "10.1"
 DataStructures = "0.18"
-ModelingToolkit = "7"
+ModelingToolkit = "7, 8"
 Symbolics = "4"
 julia = "1.6"